Method for preparing mullite-based light refractory material and synchronously purifying molybdenum calcine

Abstract

The invention discloses a method for preparing a mullite-based light refractory material and synchronously purifying molybdenum calcine. The invention belongs to the field of preparation of molybdenumchemicals and refractory materials. The method comprises the following steps: adding industrial molybdenum calcine which accounts for 100-500% of the mass of an aluminum-silicon raw material into thealuminum-silicon raw material, grinding and uniformly mixing the raw material, pressing the mixture into tablets, heating the tablet to 1000-1400 DEG C, and roasting the tablet for 0.5-3 hours, thereby obtaining the mullite-based light refractory material. In the roasting process, by collecting the condensed volatile matters at the same time, a pure molybdenum trioxide byproduct can be coproduced. The method integrates the preparation of the mullite-based light refractory material and the purification of molybdenum trioxide, wherein the production process is economic and environment-friendly,the added value of the product is high, the resource recovery rate is high, the equipment applicability is good, and the method is suitable for industrial application.

Description

technical field

[0001] The invention belongs to the field of molybdenum smelting and refractory material preparation, and in particular relates to a method for preparing mullite-based lightweight refractory material and co-producing high-purity molybdenum trioxide by using molybdenum calcined sand as a pore-forming agent. Background technique

[0002] Compared with traditional refractory materials, lightweight refractory materials have small volume density and low thermal conductivity, which help to save raw materials and fuel, reduce transportation and installation costs, and improve the working environment. Among various refractory materials, mullite (2Al 2 o 3 ·SiO2 2 ) also has the advantages of good chemical corrosion resistance and thermal shock resistance, high refractoriness, and small thermal expansion coefficient, and is very suitable for the preparation of lightweight refractory bricks.

[0003] At present, the methods for preparing porous mullite mainly includ...

Examples

Embodiment 1

[0034] Add 100% molybdenum calcined sand (Mo 60.3wt.%, SiO 2 3.0wt.%, Fe 0.9%, CaO 1.5wt.%), get Al 2 o 3 / SiO 2 =2.55, after grinding for 30 minutes with a planetary ball mill, dry-press into blocks with a force of 10 MPa, and send it into a roasting furnace for roasting. Raise the temperature to 800°C at a rate of 20°C / min (the rate of the first heating section), and then raise the temperature to 1300°C at a rate of 5°C / min (the rate of the second heating section), and keep the temperature for 2 hours. While heating, air is blown in to take away the volatilized molybdenum trioxide and cool it for collection. After heating, let the bulk material cool down to room temperature naturally with the furnace. The obtained mullite-based lightweight refractories and sublimes were tested, and the results showed that the bulk density was 0.66g / cm 3 , the apparent porosity is 74.7%, the thermal conductivity at room temperature is 0.23W / mK, the compressive strength is 13.7MPa, and th...

Embodiment 2

[0036] Compared with Example 1, the difference is only that the aluminum hydroxide in Example 1 is replaced with aluminum oxide, and other materials and operations are unchanged.

[0037] The fired mullite-based lightweight refractory material has a bulk density of 0.78g / cm 3 , the apparent porosity is 68.6%, the thermal conductivity at room temperature is 0.27W / mK, the compressive strength is 15.6MPa, and the refractoriness is 1775°C. The purity of the collected molybdenum trioxide product is 99.4%, and the recovery rate of molybdenum is 94.4%. Since the dehydration of aluminum hydroxide at high temperature itself produces more pores, but alumina cannot produce this effect, so the bulk density increases slightly, the apparent porosity decreases, and the thermal conductivity increases.

Embodiment 3

[0039] Compared with Example 2, the only difference is that the amount of molybdenum calcine added is further increased to 3 times the total mass of aluminum-silicon raw materials, and other conditions remain unchanged.

[0040] The fired mullite-based lightweight refractory material has a bulk density of 0.58g / cm 3 , the apparent porosity is 79.6%, the thermal conductivity at room temperature is 0.14W / mK, the compressive strength is 8.9MPa, and the refractoriness is 1754°C. The purity of the collected molybdenum trioxide product is 99.8%, and the recovery rate of molybdenum is 95.2%. With the increase of the amount of molybdenum calcined sand, the refractoriness of the obtained material only slightly decreased, and other indicators such as bulk density, apparent porosity, and thermal conductivity were significantly improved. In addition, because the relative impurity content of molybdenum trioxide is reduced, molybdenum recovery rate and product purity are improved.

technical field

[0001] The invention belongs to the field of molybdenum smelting and refractory material preparation, and in particular relates to a method for preparing mullite-based lightweight refractory material and co-producing high-purity molybdenum trioxide by using molybdenum calcined sand as a pore-forming agent. Background technique

[0002] Compared with traditional refractory materials, lightweight refractory materials have small volume density and low thermal conductivity, which help to save raw materials and fuel, reduce transportation and installation costs, and improve the working environment. Among various refractory materials, mullite (2Al 2 o 3 ·SiO2 2 ) also has the advantages of good chemical corrosion resistance and thermal shock resistance, high refractoriness, and small thermal expansion coefficient, and is very suitable for the preparation of lightweight refractory bricks.

[0003] At present, the methods for preparing porous mullite mainly includ...

Examples

Embodiment 1

[0034] Add 100% molybdenum calcined sand (Mo 60.3wt.%, SiO 2 3.0wt.%, Fe 0.9%, CaO 1.5wt.%), get Al 2 o 3 / SiO 2 =2.55, after grinding for 30 minutes with a planetary ball mill, dry-press into blocks with a force of 10 MPa, and send it into a roasting furnace for roasting. Raise the temperature to 800°C at a rate of 20°C / min (the rate of the first heating section), and then raise the temperature to 1300°C at a rate of 5°C / min (the rate of the second heating section), and keep the temperature for 2 hours. While heating, air is blown in to take away the volatilized molybdenum trioxide and cool it for collection. After heating, let the bulk material cool down to room temperature naturally with the furnace. The obtained mullite-based lightweight refractories and sublimes were tested, and the results showed that the bulk density was 0.66g / cm 3 , the apparent porosity is 74.7%, the thermal conductivity at room temperature is 0.23W / mK, the compressive strength is 13.7MPa, and th...

Embodiment 2

[0036] Compared with Example 1, the difference is only that the aluminum hydroxide in Example 1 is replaced with aluminum oxide, and other materials and operations are unchanged.

[0037] The fired mullite-based lightweight refractory material has a bulk density of 0.78g / cm 3 , the apparent porosity is 68.6%, the thermal conductivity at room temperature is 0.27W / mK, the compressive strength is 15.6MPa, and the refractoriness is 1775°C. The purity of the collected molybdenum trioxide product is 99.4%, and the recovery rate of molybdenum is 94.4%. Since the dehydration of aluminum hydroxide at high temperature itself produces more pores, but alumina cannot produce this effect, so the bulk density increases slightly, the apparent porosity decreases, and the thermal conductivity increases.

Embodiment 3

[0039] Compared with Example 2, the only difference is that the amount of molybdenum calcine added is further increased to 3 times the total mass of aluminum-silicon raw materials, and other conditions remain unchanged.

[0040] The fired mullite-based lightweight refractory material has a bulk density of 0.58g / cm 3 , the apparent porosity is 79.6%, the thermal conductivity at room temperature is 0.14W / mK, the compressive strength is 8.9MPa, and the refractoriness is 1754°C. The purity of the collected molybdenum trioxide product is 99.8%, and the recovery rate of molybdenum is 95.2%. With the increase of the amount of molybdenum calcined sand, the refractoriness of the obtained material only slightly decreased, and other indicators such as bulk density, apparent porosity, and thermal conductivity were significantly improved. In addition, because the relative impurity content of molybdenum trioxide is reduced, molybdenum recovery rate and product purity are improved.